Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 7a5dbe88bdaf6368…

MALICIOUS

Office (OLE) / .XLS

94.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-07-04
MD5: 528e2bc4ae098c99e15d8670aeefd145 SHA-1: 0194c8975acb6cae02af2f93a35876cbabfd1c56 SHA-256: 7a5dbe88bdaf6368e14bfc8082e127ab7bca8665bad8cfdd45dfd27ee3659bb0
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File

The sample contains Excel 4.0 macros, specifically an Auto_Open function that utilizes dangerous API calls like RUN. ClamAV identifies this as an Emotet downloader variant. The macro's purpose is to execute a secondary payload, likely downloaded from a remote source, which is characteristic of Emotet's infection chain.

Heuristics 4

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • ClamAV: Xls.Downloader.Emotet-ea81817e7f807ab1-9952142-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-ea81817e7f807ab1-9952142-0
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
284f2836f30d4f529f3f67110b3bfb73d5b26e67c353e36fa87f86510408efa8
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8144 bytes